The present invention relates to furniture for seating having a frame, the larger portion of which is made with a molding process. In particular, the invention relates to a frame having molded components which are largely shell-structure, in which a lattice form is defined by the molded components around a recessed or open area e.g., within the seat portion of the seat frame, and which may optionally be upholstered.
Furniture for seating is typically made by providing a weight-bearing frame and, in many cases, a suspension and foam or other padding and upholstery.
A significant portion of seat frames are of conventional construction. The overwhelming majority of upholstered seat frames are of conventional construction. The conventional construction of seat frames is the familiar frame construction seen in most furniture, and especially in most upholstered furniture. In it, conventional materials such as hardwood, softwood, plywood, chipboard, and extruded steel members, are processed by conventional means such as sawing, milling, planing, etc., and joined using conventional materials and methods such as screw and glue joinery, staple gun joinery, welding, rabbeting, and the like. The conventional construction of seat frames is limited as a process of manufacture. The conventional construction of seat frames is limited as regard to the intended use, and potentially desired capabilities for use, of the seat frame. The limitations of conventional construction are particularly significant for seat frames that are upholstered.
Seat frames of conventional construction are poorly equipped to provide higher quality and greater value at modest or reduced cost. The materials and processes of the conventional construction severely limit the range of properties that can be provided in a seat frame, particularly at modest cost. Seat frames of conventional construction are not efficiently produced. Extensive pre-processing of materials is usually required, and assembly processes are usually cumbersome and labor-intensive, leading to poor cost-efficiency. Labor in many cases accounts for nearly 50% of value-added cost of manufacture. The conventional construction can result in inconsistencies in product quality. The high labor content in the manufacturing process is a contributing factor, as are conventional frame materials, particularly wood-based materials, which are often idiosyncratic and inconsistent.
The engineering capabilities in seat frames of conventional construction are limited. The properties, structural and otherwise, that can be engineered into the seat frame, especially at modest cost, are limited. Conventional seat frames are often governed by strict perpendicularity at places of intersection where the component parts join, and the nature of the joinery often provides for non-optimal strength and durability. The design capabilities in seat frames of conventional construction are limited. It is not feasible to produce a generous range of forms, especially at modest cost. Conventional seat frame designs incline to a rigid, rectilinear format. Ergonomic features such as lumbar support, are poorly accommodated. Seat frames of conventional construction are often difficult to recycle, since the hardware used in the joinery frequently differs from the material from which the frame is made and must be removed, often with some difficulty.
The forms that are usually provided within the frames of seat frames of conventional construction are not especially well-suited for use with upholstered furniture. Seat frames of conventional construction tend to provide surfaces that are lean and narrow. Furthermore, components are typically rectangular in cross-section, defining sharp edges. Thus, in such furniture, large quantities of, typically expensive, foam or padding are usually required to provide upholstered furniture which can accommodate the human body with some degree of comfort (overstuffed upholstered furniture being a typical, and frequent, expression of this). And, despite the large quantities of foam or padding usually demanded, coverage of the frame with such foam or padding is usually not complete, often reducing the useful life of the upholstery, often limiting the fabric materials available for use with the upholstered seat frame to xe2x80x9cupholstery gradexe2x80x9d materials, and often further limiting the ease with which upholstered pieces can be transported (already usually burdened by the relatively great weight of the frames). The (typical) rectilinear format of conventional seat frame designs tends to restrict the ability to facilely produce seat frames or seat frame components that stack or internest.
Some furniture is designed to be xe2x80x9cknocked-downxe2x80x9d (i.e. disassembled and/or folded so as to occupy a smaller volume than in the normal use configuration). Seat frames of conventional construction typically require added hardware in order for the frames to be knocked-down, adding the cost of fitting and joining such additional hardware to the seat frame. The various seat frame designs must be accommodated to the available knock-down hardware. The material of which such added hardware is made typically differs, both in composition and strength, from the material from which the seat frame is made, resulting in stress raisers (concentrations of stress in a relatively small region) that reduce the durability of the seat frame. The added hardware also makes the seat frame more difficult to recycle. Many knock-down designs are relatively difficult to disassemble and reassemble. Among other things, this has limited the use of knock-down seat frames with modular-like interchangeable parts or sections.
Some furniture provides for relative movement of components (e.g. recliners, sofa beds, seat frames with adjustable headrests or adjustable armrests). In conventional seat frame construction these typically have been produced by joining separate hardware devices (such as hinges and other pivots, sliding hardware and the like) to portions of the frame. These designs suffer from defects similar to those described for knock-down devices (such as cost, limitation of designs to available hardware, stress raisers and difficulty of recycling).
Devices or techniques for therapeutic or comfort enhancement such as massage, heating, pneumatic variable body support, etc. are typically coupled to the seat frame by conventional means. Design and engineering capabilities for the incorporation of such devices or techniques are restricted by the limited engineering capabilities of conventional seat frame construction, i.e. the properties, structural and otherwise, that can be engineered into the seat frame, especially at modest cost. Design and engineering capabilities for the incorporation of such devices or techniques are also restricted by the limited design capabilities of conventional seat frame construction, and the limited range of forms that can be produced, and are at least partially defined by the typically rigid, rectilinear conventional seat frame format.
Because of limitations on design and engineering capabilities in conventional seat frame construction, such as those indicated above, it is impossible for producers of conventional seat frames to fully realize the benefits of modem design tools such as computer-based visualization and 3-D modeling, structural analysis, process simulation, rapid prototyping and computer-driven tools. Limits in design and engineering capabilities also result in a limited range in the choices available for custom-designed and engineered seat frames and upholstered units.
There are fundamentally sound reasons for manufacturing a seat frame comprised largely or entirely of a molded article or molded articles (molded seat frames). The capabilities of molded construction generally, applied to the manufacture of seat frames, can answer to the limitations of the conventional construction of seat frames, limitations both as process of manufacture, and limitations as regard to the intended use, and potentially desired capabilities for use, of the seat frame. The advantages of molded construction are especially useful for seat frames that are upholstered. The presence of molded seat frames has increased in recent years, mostly by way of injection-molded chairs made of plastic. The capabilities of molded construction generally, applied to the manufacture of seat frames, have been only modestly realized. Very few molded seat frames are upholstered.
Molded seat frames are well-equipped to provide higher quality and greater value at modest or reduced cost. Molded seat frames greatly expand the range of properties that can be provided in a seat frame, particularly at modest cost. Molded seat frames can be efficiently produced. Often no pre-processing of materials is necessary, and assembly processes can be simplified or eliminated. Molded seat frames can be produced with consistent product quality. The technology of molding is advanced, and continues to advance.
The engineering capabilities in molded seat frames are broad. The properties, structural and otherwise, that can be engineered into the seat frame, especially at modest cost, are broad. Molded seat frames need not be governed by strict perpendicularity, nor have joinery providing non-optimal strength and durability. The design capabilities in molded seat frames are broad. It is possible to produce a generous range of forms, and at modest cost. Seat frame designs need not incline to a rigid, rectilinear format. Ergonomic features such as lumbar support, can be readily accommodated. Molded seat frames need not be difficult to recycle, as joinery can be made integral, or eliminated entirely.
Molded seat frames are well-suited for use in upholstered furniture. Molded seat frames need not provide surfaces being lean and narrow. Molded seat frames need not be rectangular in cross-section, defining sharp edges. Use of the molded seat frame in upholstered furniture makes special sense. Molding makes a wide range of materials available, and with upholstered furniture the seat frame need not be exposed, so the aesthetic properties of the molded materials need not be a concern. Molded seat frames provide great opportunity to produce seat frames or seat frame components that stack or internest.
Molded seat frames that xe2x80x9cknock-downxe2x80x9d can be made without added hardware, instead having integral knock-down joinery. Thus, no cost need be incurred in fitting and joining additional hardware to the seat frame, the seat frame designs need not be accommodated to available knock-down hardware, no stress raisers need result that reduce the durability of the seat frame, and the seat frame can be less difficult to recycle. Integral knock-down joinery in molded seat frames can be made to be readily disassembled and reassembled.
Molded seat frames providing for relative movement of components may be made without added hardware, instead having integral joints and the like for motion. The advantages are similar to those described for molded seat frames having integral knock-down joinery (such as cost-savings, the independence of designs from available hardware, reduced stress raisers and increased ease of recycling).
In molded seat frames, devices or techniques for therapeutic or comfort enhancement such as massage, heating, pneumatic variable body support, etc., can be readily incorporated into the seat frame, and by novel means. Design and engineering capabilities for the incorporation of such devices or techniques are enhanced by the broad engineering capabilities of molded seat frames. Design and engineering capabilities for the incorporation of such devices or techniques are enhanced by the broad design capabilities of molded seat frames, and the broad range of forms that can be produced.
Because the design and engineering capabilities in molded seat frames are broad, producers of molded seat frames can fully realize the benefits of modern design tools such as computer-based visualization and 3-D modeling, structural analysis, process simulation, rapid prototyping and computer-driven tools. Broad design and engineering capabilities in molded seat frames also result in a broad range in the choices available for custom-designed and engineered seat frames and upholstered units.
Molded seat frames fall into two fundamental categories, reflecting two generally distinct approaches to the engineering of strength within molded articles: (1) Molded seat frames having an engineering of strength within molded articles largely being as that largely evident in current injection-molded plastic chairs; (2) Molded seat frames having an engineering of strength within molded articles largely being shell-structure (shell-structure molded seat frames). The latter is preferable in many ways, and particularly so for molded seat frames that are upholstered.
In shell-structure molded seat frames, considerable continuity in structural strength in the seat frame, i.e. structural integration, i.e. diminishment of stress raisers between portions of the seat frame, can be readily achieved. This is not the case with current injection-molded plastic chairs, for a distinct discontinuity in structural strength in the seat frame, between the seat portion of the seat frame and surrounding areas, is common and not always easily redressed. Continuity in structural strength makes the seat frame more stable, enhancing strength and durability. It can also reduce the quantities of material required, and make engineered strength more predictable.
In shell-structure molded seat frames, structural properties are enhanced in making the forms wanted for upholstered furniture. Forms that are in size less lean, less narrow, broader, fuller, can enhance overall structural strength in a shell-structure. Forms that are in shape less rectangular, less sharp-edged, more rounded, blunter of edge, preferably generously contoured, can enhance structural integration, durability, efficiency of material use, and torsional strength, in a shell-structure. Shell-structures lend themselves to a disassembly and reassembly through means of overlapping the shell-structure. This can allow for strong, structurally integrated joints, that can be facilely disassembled and reassembled. Shell-structures that are hollow allow a stacking or internesting of the disassembled portions of the seat frame, and through this means, a larger seat frame might be reduced in size to a very modest package.
There are a range of molding processes that by their very nature are inclined to produce shell-structures (molding processes intrinsically descriptive of shell-structures). In shell-structure molded seat frames these molding processes can be utilized, bringing great advantages to the producer. In shell-structure molded seat frames made with molding processes intrinsically descriptive of shell-structures, a way of working a material is fluently integrated with a way of using the so-worked material in the engineering of the structure, incorporating the natural capabilities of a characteristic materials processing with a characteristic structural engineering.
The range of molding processes being intrinsically descriptive of shell-structures makes more molding processes available for shell-structure molded seat frames. Included among these are low-cost molding process options using lower-cost molds and molding machinery (costs should be compared with the injection-molding process of current injection-molded plastic chairs, where mold costs can run to several hundred thousand dollars, for single-seat sized chairs, and the cost of the injection-molding machinery used can run into the millions of dollars). Notable among the low-cost molding options are low-pressure molding processes, such as a process operating at pressures less than about 100 p.s.i., preferably less than 50 p.s.i. These especially can reduce molding costs, allowing lighter, thinner molds, and in some cases facilitating a faster cooling of material, as applicable. In some instances, very lightweight molds can be made having strength mirroring that of the shell-structure molded article. Low-pressure molding processes also enable many variations within the molding process. Complex inter-inflatable moldable forms can be used in low-pressure molding processes. Innovative molding processes such as molds that are an inflatable article can be used. Using molds that are an inflatable article, seat frames can be transported unconstructed and be molded directly by the end user. A canister of material with foaming agent, for example, can be shipped with the inflatable mold. The availability of low-cost molding options, and particularly lower-cost molds, means that large molds (as. for two-seat or three-seat frames) need not be prohibitively expensive. It means a reduction in the size of production runs required to recoup mold costs, so designs can be turned over more readily, increasing design flexibility for producers, and enabling an avoidance of clichxc3xa9d designs (clichxc3xa9d designs being common with current injection-molded plastic chairs). It also means producers can affordably keep many molds on hand, and enables frames or components of frames in varying sizes, in varying versions, with varying ergonomic features, and the like.
Many materials, in many states, are accessible with molding processes intrinsically descriptive of shell-structures, making more materials available for use with shell-structure molded seat frames. Among materials available are many alternatives to plastics. The use of plastics in molded seat frames raises environmental considerations, especially questions as to the material""s long-term recyclability. But perhaps more importantly, seat frames made of plastic present a fire safety hazard and may not be well-suited for use indoors, especially in homes in the form of upholstered furniture.
The many molding processes intrinsically descriptive of shell-structures, and the many materials accessible through them, provides great flexibility for the producer of shell-structure molded seat frames. There are many options for the producer to choose among molding processes and materials, or molding contractors and material suppliers. The producer can tap this range of molding processes and materials, or molding contractors and material suppliers, for rapid, localized or decentralized growth. Growth may also possibly be attained without heavy capital requirements by tapping the financial base of competing molding contractors and material suppliers seeking avenues for their production. Because of the ability to diversify production, the producer need not be tied to any particular molding process or molding contractor, or material or material supplier. The producer is free to adjust production to accommodate changes in material costs, molding costs, or other concerns. The producer can target various price points in the market, with seat frames made of various materials, or processes. A consumer can purchase a favored seat frame in a lower-cost version (where the seat frame is upholstered, choosing say, to initially focus on premium upholstery), then upgrade later to a more expensive version of the same frame (e.g., stronger and/or more durable, or with additional features such as disassembly, therapeutic features, etc.). The producer is also accorded greater flexibility for incorporating developments in materials and production technology.
Cast-in stresses in molded articles generally are reduced in molding processes intrinsically descriptive of shell-structures, because the molded malleable material, in contacting and taking its shape from the defined, moldable form, is apt to travel in volumes that are broad, and travel at and onto the outer surface area. Cast-in stresses in molded articles can lead to stress-cracking and reduce a molded article""s useful life, and are a matter of concern in current injection-molded plastic chairs. The engineering capacity in molded articles produced using molding processes intrinsically descriptive of shell-structures is furthered in that the malleable material, in contacting and taking its shape from the defined form, is apt to travel in volumes that are broad, and travel at and onto the outer surface area, and the material can often be selectively distributed on the outer surface area. With many of the molding processes intrinsically descriptive of shell-structures closed shell construction shell-structures can be readily produced. This is of great value in that closed shell construction shell-structures are particularly well-suited for use in upholstered furniture, providing surface area around all parts of the seat frame. Further, closed shell construction shell-structures can enhance the torsional strength and durability of the seat frame, and provide advantages in seat frames having a disassembly and reassembly of seat frame components.
Forms that are scaled, that are in size less lean, less narrow, broader, fuller, wanted for upholstered furniture, further the distribution of material in molding processes intrinsically descriptive of shell-structures. Forms that are contoured, that are in shape less rectangular, less sharp-edged, more rounded, blunter of edge, preferably generously contoured, wanted for upholstered furniture; significantly improve the distribution of material, and facilitate the pulling of finished parts from molds, in molding processes intrinsically descriptive of shell-structures.
Shell-structure molded seat frames have been made for over 50 years. They have been produced with a range of molding processes, and in a range of materials. The role of shell-structure molded seat frames in the furniture industry has however always been a modest one. As the capabilities of molded seat frames have been only modestly realized, so too have the capabilities of shell-structure molded seat frames. The advantages shell-structure molded seat frames provide for use in upholstered furniture has not been significantly recognized. Very few shell-structure molded seat frames outside of office chairs have been upholstered. No upholstered shell-structure molded seat frames of the likes of traditional upholstered sofas, loveseats and chairs, it is believed, have achieved significant commercial success.
Previous shell-structure molded seat frames particularly suffer these limitations:
Previous shell-structure molded seat frames do not make as effective a use as is possible of shell-structure strength in assuming compressive loading on the seat frame. This limits the breadth of spans shell-structure molded seat frames are capable of traversing, and the loads they are capable of assuming, without undue excess of material, and limits the range of designs and uses available to them. The durability or life-span of shell-structure molded seat frames is reduced because of the ineffective use made of shell-structure strength in assuming compressive loading, and/or inordinate strains being placed on a portion of the seat frame. The materials being available for use in shell-structure molded seat frames is diminished, especially for materials likely to be incapable of accepting the strains of an inefficient assumption of bending loading, such as paper or paper/fiber composites.
Previous shell-structure molded seat frames are not exceptionally well-suited for use in upholstered furniture. Previous shell-structure molded seat frames usually do not provide recessed or open area within the seat portion of the seat frame such as might accommodate a suspension. Previous shell-structure molded seat frames do not accommodate a suspension comprised of a fabric material which can wrap around all sides of the seat portion of the seat frame, giving firm support to the fabric material suspension, and distributing strain evenly across the seat frame. Previous shell-structure molded seat frames do not provide multiple options for upholstering.
Previous shell-structure molded seat frames provide less than optimal opportunities for assembly and disassembly of the seat frame. Limited opportunities for assembly and disassembly reduce the molding processes available for the seat frame""s manufacture and may decrease the range of materials available to it. Limited opportunities for assembly and disassembly decrease the options available in the packaging and transport of the seat frame. Limited opportunities for assembly and disassembly decrease options for an interchanging of parts or sections of the seat frame. Movable parts or sections are not readily incorporated in previous shell-structure molded seat frames.
Previous shell-structure molded seat frames do not have the advantage of the light weight and efficient material use of space-frames for carrying compressive loads, nor join the advantages of the light weight and efficient material use of space-frames for carrying compressive loads with the efficiency of shell-structures for resisting shear and torsion. Previous shell-structure molded seat frames do not define a space-frame being scaled and contoured to enhance the properties of the seat frame for use in upholstered furniture while also providing a seat frame having exceptional structural integration and torsional strength. Previous shell-structure molded seat frames do not have the added design and engineering flexibility provided by space-frames for selectively positioned structural members. Previous shell-structure molded seat frames do not have the added design and engineering flexibility of structural strength in individual structural members being selectively described.
The present invention includes the recognition of problems found in the previous devices. The present invention includes the recognition of problems in seat frames of conventional construction, advantages in seat frames being of a molded construction, advantages in seat frames of a molded construction being shell-structure molded seat frames, and the recognition of problems in previous shell-structure molded seat frames.
According to an aspect of the present invention, the furniture is provided with a weight-bearing frame largely comprised of one or more molded components, where the molded components are largely shell-structure, and where a lattice form is defined by the molded components around a recessed or open area within the seat portion of the seat frame. Preferably, the lattice form defined has the character of a skeletal framework. Preferably, the molded components are scaled and contoured. Preferably, scaling and contouring provides substantial structural integration and torsional strength in the structure defined by the molded components. Preferably, the lattice form defines a lattice structure. A lattice structure differs from a lattice form in that a lattice form may be a representation of the form or a less than fully integrated structural unit, while a lattice structure necessarily functions as a significantly integrated structural unit. Preferably, the lattice form defines a lattice structure in the form of a space-frame. Preferably, substantially all of the weight-bearing portions of the frame are molded components.
In some embodiments, the furniture is upholstered. Preferably the upholstery and/or foam or padding and/or suspension is made of elements which can be readily put together and taken apart, e.g. by the user, preferably such that the user can readily substantially alter the appearance and/or feel of the furniture by xe2x80x9cdressingxe2x80x9d the same frame in different upholstering units. Preferably upholstery and/or suspension materials define space in and around the frame in varied ways, with a plurality of formats of xe2x80x9cdress,xe2x80x9d with upholstery and/or suspension materials spanning or encircling parts of the frame, and the like. In one embodiment, in coupling to the frame, upholstery and/or foam or padding and/or suspension pass through an opening defined in the inner region of the frame.